There are large drilling rigs specially designed to be airlifted by helicopter into locations inaccessible by other forms of transportation. Therefore, there is also a need for a mud pump which can be easily broken down, or disassembled, into packages of a size which can be lifted by a helicopter into remote drilling locations. Presently available mud pumps which are light enough to be airlifted are smaller than desired for drilling rigs, and in order to attain the required flow, these pumps must be operated at speeds which cause high maintenance problems. Therefore, it is desirable to have made available a pump apparatus which has the required capacity and which can be dismantled into convenient packages for helicopter transport.
The present invention achieves the above desired results by the provision of a pump having three single acting cylinders, commonly known as a triplex pump. Rather than dismantling the pump into a power end component and fluid end component as has been in the past, the pump is designed as a three single cylinder assembly, wherein each cylinder is a single acting pump (simplex) with the shaft ends of each simplex pump being axially aligned with one another and connected together with special couplings so that the throws of the three crankshafts are timed 120.degree. apart in order to have a balanced throw and discharge flow.